Malodors are offensive odors, which are encountered in the air and on many substrates such as fabrics, hard surfaces, skin, and hair. Malodors have either personal or environmental origin. For example sweat, urine, and feces malodors are personal in origin, whereas, kitchen, gasoline, cooking, tobacco smoke, etc. malodors are of environmental origin. While personal malodors are easily deposited on fabric, hair, and skin, environmental malodors also have a propensity to deposit on these substrates. Combinations of personal and environmental malodors make up a composite malodor, which has many oil soluble, water soluble, and solid components that have a vapor pressure at ambient temperatures, which is why humans can detect them.
Amines, thiols, sulfides, short chain aliphatic and olefinic acids, aldehydes, and esters form the largest and most unpleasant chemical groups found in sweat, household, and environmental malodors. These types of malodors typically include indole, skatole, and methanethiol found in toilet and animal odors; piperidine and morpholine found in urine; pyridine and triethyl amine found in kitchen and garbage odors, such as fish; hydrogen sulfide, nicotine, and various pyrroles found in cigarette smoke odors; and short chain fatty acids in axilla malodors.
Several approaches have been used to counteract malodors. These approaches include masking by superimposing the malodor with a pleasant stronger odor, cross-adaptation by blocking of the malodor olfactory receptors, suppression of the malodor by mixing with an ingredient that causes a negative deviation of Raoult's law, elimination of the malodor by chemical reaction, absorption of the malodor by a porous or cage-like structure, and avoidance of the formation of malodors by such routes as antimicrobials and enzyme inhibitors. All of these approaches are deficient, however, because they provide a perfumer with only limited options for malodor counteractants. Accordingly, there is still a need for additional and improved malodor counteractancy compositions.
It is known that fragrances may be designed to counteract malodors. The fragrance materials, which are most common to mask a malodor are those that contain a carbon-carbon double bond conjugated with one or more carbonyl groups. Aldehydes are the most commonly used materials of this class for malodor counteractancy, the most commonly used for deodorant properties are trimethyl hexanal, other alkyl aldehydes, benzaldehyde, and vanillin. For example, European Patent Application 0404470 discloses the use of fragrance materials with good malodor reduction efficacy, and European Patent Application 0545556 discloses mixtures of fragrance materials that mask malodors. The use of fragrance materials alone, however, may limit the types of fragrances a perfumer can create.
Other materials have also been shown to have malodor counteractancy (MOC) properties. Schleppnik, U.S. Pat. No. 4,622,221 (“Schleppnik '221”) discloses the use of cyclohexyl alcohols and ester derivatives in room fresheners. Kulka, U.S. Pat. No. 3,074,891 discloses esters of alpha-, beta-unsaturated monocarboxylic acids as malodor counteractants. Kulka, U.S. Pat. No. 3,077,457 discloses fumaric acid esters as malodor counteractants. Schleppnik, U.S. Pat. No. 4,187,251 discloses alkyl cyclohexyl alkyl ketones as malodor counteractants. Schleppnik, U.S. Pat. No. 4,310,512 discloses the use of derivatives of acetic and propionic acids, and Schleppnik et al., U.S. Pat. No. 4,009,253 discloses the use of 4-cyclohexyl-4-methyl-2-pentanone as a malodor counteractant. These materials, however, are not capable of neutralizing all types of functional groups contained in malodor molecules. All of the U.S. patents discussed above are hereby incorporated by reference as if recited in full herein.
Unsaturated non-perfumery chemical compounds have also been shown to act as effective deodorants on the basis that many reactive odor-causing molecules may be eliminated by addition across the double bond. Unfortunately, many of the unsaturated compounds themselves have very unpleasant and offensive odors.